Inhibitors of the HIV viral protease are presently considered the most effective drugs against HIV infection. Unfortunately, most current proteases inhibitors are relatively large hydrophobic molecules that possess rather low bioavailability. A high pill burden is therefore required to attain the therapeutic dose in a patient. This is a deterrent, which too often results in patient non-compliance and inadequate treatment results. This situation leads to sub-optimal therapeutic drug concentration that in turns leads to the development of HIV resistant strains. Consequently, there is an urgent need to improve the solubility and bioavailability of proteases inhibitors.
A unique class of amino acid based HIV protease inhibitors have been described in international application No. PCT/CA02/00190 published under No. WO02/064551 on Aug. 22, 2002 the entire content of which is incorporated herein by reference.
Aromatic derivatives have also been described in U.S. Pat. No. 6,632,816 to Stranix et al, the entire content of which is incorporated herein by reference. This patent includes, more particularly, N,-synthetic amino acid substituted L-lysine derivatives possessing potent aspartyl protease inhibitory properties. However, it would be advantageous to improve these derivatives by enhancing aqueous solubility and bioavailability in order to reduce the pill burden and to favour patient's compliance. Since it is challenging to generate active protease inhibitors, specifically toward wild-type and resistant strains, the formation of derivatives of original HIV protease inhibitors such as inhibitors described in U.S. Pat. No. 6,632,816 to Stranix et al, known to be active toward resistant strains represents a viable route with considerable advantages. More particularly, generation of compounds with enhanced aqueous solubility, bioavailability, time of duration and formulation properties along with other advantages is desirable in the development of an effective drug.
Compounds with improved solubility and bioavailability have been described in U.S. application Ser. No. 10/902,935 published under No. 2006-0025592A1 on Feb. 2, 2006 in the name of to Stranix et al. These compounds were found to be suitable for oral administration in aqueous solution.